Kids like to create faux lip, nose or tongue rings by fashioning the balls into magnetic loops, which wind up accidentally getting swallowed

Doctors are reporting rising incidences of children eating high-powered magnets—usually in the form of those little silver magnetic balls that can be shaped into pyramids and linked into ropes. When a child ingests more than one of these balls, they do what magnets do—stick together—within the curious kid’s stomach. This can wreck havoc on the intestines, even tearing holes in those delicate organs.

These magnets, CNN reports, are not the run-of-the-mill refrigerator variety:

Called “rare earth” or “neodynium” magnets, they’re much more powerful than their regular counterparts.

Dr. Steven Schwarz, a professor of pediatrics at Downstate Medical Center in New York, knows how strong these magnets’ attraction really is. He recently removed a bracelet made of 29 high-powered magnets from the stomach of a 13-month-old girl.

“It’s not easy to pull them apart,” he says. “You can feel the resistance.”

As of 2008, CNN reported last year, around 200 cases had been reported. But no one knew the true number of kids who wound up in emergency rooms after putting the shiny balls into their mouths.

Now, a new paper published in the journal Annals of Emergency Medicine clarifies the true scale of the problem and confirms that it’s on the rise. The authors monitored cases of magnet ingestion between 2002 and 2012, finding that the incidents increased by a factor of five over that time period. All together, more than 22,500 cases were reported during that time period, and the injuries really picked up from 2007 onwards.

Not surprisingly, the authors found, the more magnets a child ate, the more serious the potential damage. Sometimes, these cases required emergency surgery. Sometimes, CBS Pittsburgh reports, kids turn up in the emergency room with up to 20 magnetic balls in their bodies.

You might think this may be a bigger issue for toddlers who put everything in their mouths, but it’s actually older kids. The average age was around 5 for swallowing, and around 10 for inhaling.

Sometimes, older kids like to create faux lip, nose or tongue rings by fashioning the balls into magnetic loops, which occasionally wind up accidentally getting swallowed. CBS reports that the average age for a mouth-ingested ball is 5, whereas a nose-snorted ball is 10.

In January this year, the Consumer Product Safety Commission issued a recall for some of these magnetic sets, pointing out that when “two or more magnets are swallowed, they can link together inside a child’s intestines and clamp onto body tissues, causing intestinal obstructions, perforations, sepsis and death.” Anyone who turns in their magnetic ball kits will be issued a $20 store credit voucher.

Here’s a video warning about the magnets and demonstrating how they wreck havoc in the intestines: